The present invention relates to new formulations and, in particular, to new UV-protection formulations which comprise a micronised UV absorber, wherein the micronised UV absorber is present in the oil phase of the formulation.
It has long been known that prolonged exposure to UV radiation which reaches the surface of the earth can lead to the formation of erythemas or light dermatoses, as well as to an increased incidence of skin cancers, or accelerated skin ageing.
Various sunscreen formulations have been proposed which include a material which is intended to counteract UV radiation, thereby inhibiting the said undesired effects on the skin.
A great number of compounds has been proposed for use as UV protectants in sunscreen formulations, especially soluble organic UV absorbers and insoluble micronised inorganic compounds, in particular zinc oxide and titanium dioxide.
With respect to the use in sunscreen formulations of soluble organic UV absorbers, they have the disadvantages that their effectiveness as UV protectants in terms of SPF (Sun Protection Factor) in a sunscreen formulation is often too low for commercial purposes; as a result of their solubility, they exhibit relatively high allergenic potential; and that as a result of intrinsic photochemical lability, the duration of the protective effect is often too low.
The high specific weight of insoluble inorganic compounds, such as titanium dioxide leads to a reduced stability of formulations containing them. Moreover, such inorganic compounds have been claimed to generate toxic radicals under the influence of light and water (xe2x80x9cRedox Mechanisms in Heterogeneous Photocatalysisxe2x80x9d, Serpone et al, Electrochemistry in Colloids and Dispersions, Editors Mackay and Texter, VCH Publishers Inc., NewYork 1992).
In GB-A-2303549, there is described a method of producing micronised, insoluble organic UV absorbers, as well as a sunscreen composition comprising a) 0.1 to 15%, preferably 0.5 to 10% by weight, based on the total composition of a micronised formulation of an insoluble organic UV absorber, produced according to the said method; and optionally b) a cosmetically acceptable carrier.
Micronised, insoluble organic UV absorbers so obtained, when used in sunscreen formulations, provide excellent UV protection and have at least as high an SPF rating as corresponding sunscreen formulations containing a known inorganic UV absorber. Unlike the latter UV absorbers, micronised, insoluble organic UV absorbers show no tendency, under the influence of light, to generate radicals which could damage or sensitise human skin.
In a further development of the concept disclosed in GB-A-2303549, it has now been found that, micronised, insoluble organic UV absorbers which are present in the oil phase of the sun screen formulation surprisingly show a significant improvement in sun protection.
Accordingly, the present invention provides, as a first aspect, a sun screen formulation, which is especially suitable for use in pharmaceutical or cosmetic applications, comprising
(a) a micronised organic UV absorber; and
(b) a cosmetically acceptable carrier,
wherein the micronised organic UV absorber is present in the oil phase of the formulation.
The micronised organic UV absorber, component (a), is preferably produced by the method described in GB-A-2303549, namely by a process which comprises grinding an organic UV absorber, in coarse particle form, in a grinding apparatus, in the presence of 1 to 50%, preferably 5 to 40% by weight, based on the micronised organic UV absorber, of an alkyl polyglucoside having the formula CnH2n+1O(C6H10O5)xH, in which n is an integer ranging from 8 to 16 and x is the mean polymerisation level of the glucoside moiety (C6H10O5) and ranges from 1.4 to 1.6, or an ester thereof.
The grinding apparatus used to produce the micronised organic UV absorber may be, e.g., a jet, ball, vibration or hammer mill, preferably a high speed stirring mill or impact mill, especially a rotating ball mill, vibrating mill, tube mill or rod mill.
The alkyl polyglucoside may consist of a C1-C12ester of the compound of formula CnH2n+1O(C6H10O5)xH, namely an ester formed by reacting a C1-C12acid, such formic, acetic, propionic, butyric, sulfosuccinic, citric or tartaric acid, with one or more free OH groups on the glucoside moiety (C6H10O5).
The micronised organic UV absorber may be incorporated into the oil phase with different methods.
In a preferred incorporation method the micronised organic UV absorber may be incorporated as powder. For this purpose the micronised organic UV absorber may be subjected to known powdering processes like solvent precipitation, vacuum spraying from solvents etc. These powders have a particle size of 0, 1 nm to 2 xcexcm. In order to prevent agglomeration processes the micronised organic UV absorber may be coated before powdering with a surface active agent like nonionic, anionic, cationic or amphoteric surfactants like phospholipids or known polymers, for example PVP, acrylates etc.
As example, a water-soluble surfactant or emulsifier is added to the aqueous suspension of the micronised organic UV absorber. The mixture is then spray-dried. During the spray-drying process the surfactant or emulsifier sheathes the micro-particles in form of a thin film and inhibits aggregation or facilitates the re-dispersion to the desired particle size in the oil phase.
In another preferred method the micronised organic UV absorber may be transferred to the oil phase during the preparation of the sun screen formulation: when mixing the micronised organic UV absorber which was produced by aqueous grinding with the oil phase of the sun screen formulation the water will be removed by known methods like vacuum removal. By this measure the micronised organic UV absorber will be transferred to the oil phase of the formulation.
Furthermore, it was observed that the micronised organic UV absorber which is present in the aqueous phase of the sun screen composition will migrate into the oil phase after a couple of days or weeks.
Therefore, another aspect the present invention refers to a method of preparation of the sunscreen composition by micronising the organic UV absorber in the first step as aqueous suspension, mixing the micronised organic UV absorber with the oil phase of the sunscreen composition in a second step and storing the formulation for at least three weeks in a final step.
Suitable organic UV absorber may be, e.g., a triazine, a benzotriazole, a vinyl group-containing amide, a cinnamic acid amide or a sulfonated benzimidazole UV absorber.
A preferred class of triazine compounds is that having the formula 
in which
R1, R2 and R3, independently, are H; OH; C1-C3alkoxy; NH2; NHxe2x80x94R4; N(R4)2; OR4, wherein R4 is C1-C3 alkyl; phenyl; phenoxy; anilino; pyrrolo, in which the respective phenyl, phenoxy or anilino, or pyrrolo moieties are not substituted or substituted by one, two or three substitutents selected from OH, carboxy, COxe2x80x94NH2, C1-C3alkyl, C1-C3alkoxy, a methylidenecamphor group, a group xe2x80x94(CHxe2x95x90CH)mC(xe2x95x90O)xe2x80x94OR4, a group 
xe2x80x83or the corresponding alkali metal, ammonium, mono-, di- or tri-C1-C4alkylammonium, mono-, di- or tri-C2-C4alkanolammonium salts, or the C1-C3alkyl esters thereof, a radical of formula (1a) 
R5 is hydroxy; C1-C5alkyl that is unsubstituted or substituted by one or more OH groups; C1-C5alkoxy; amino; mono- or di-C1-C5alkylamino; M; a radical of formula 
Rxe2x80x2, Rxe2x80x3 and Rxe2x80x2xe2x80x3 are each independently of the others C1-C14alkyl that is unsubstituted or substituted by one or more OH groups;
R6 is hydrogen; M; C1-C5alkyl; or a radical of the formula xe2x80x94(CH2)m2xe2x80x94Oxe2x80x94T1;
M is a metal cation;
T1 is hydrogen; or C1-C8alkyl;
m is 0 or 1;
m1 is from 1 to 5;
m2 is from 1 to 4;
m3 is from 2 to 14.
Preferred compounds of formula (1) are those having the formula 
in which
R7 and R8, independently of one another, are C1-C18alkyl; C2-C18alkenyl; a radical of the formula xe2x80x94CH2xe2x80x94CH(xe2x80x94OH)xe2x80x94CH2xe2x80x94Oxe2x80x94T1; or; a radical of the formula xe2x80x94(CH2)"Parenclosest"m1O"Parenopenst"(CH2)"Parenclosest"m2T2; a radical of the formula 
R9 is a direct bond; a straight-chain or branched C1-C4alkylene radical or a radical of the formula xe2x80x94Cm1Hxe2x80x942m1 or xe2x80x94Cm1Hxe2x80x942m1Oxe2x80x94;
R10, R11 and R12, independently of one another, are C1-C18alkyl; C1-C18alkoxy or a radical of the formula 
R13 is C1-C5alkyl;
T1 is hydrogen; or C1-C8alkyl;
m1, m2 and m3, independently of one another, are 1 to 4;
p1 is 0 or a number from 1 to 5;
A1 is a radical of the formula 
R14 is hydrogen; C1-C10 alkyl, xe2x80x94(CH2CHR16xe2x80x94O)n1xe2x80x94R15; xe2x80x94CH2xe2x80x94CH(xe2x80x94OH)xe2x80x94CH2xe2x80x94Oxe2x80x94T1; or a radical of the formula xe2x80x94(CH2)"Parenclosest"m1O"Parenopenst"(CH2)"Parenclosest"m2T2;
R15 is hydrogen; M; C1-C5alkyl; or a radical of the formula xe2x80x94(CH2)m2xe2x80x94Oxe2x80x94T1;
R16 is hydrogen; or methyl;
Q1 C1-C18alkyl;
M is a metal cation; and
n1 is 1-16.
Preferred compounds of formula (2) are those of formulae 
the formula 
in which
R17 and R18, independently of one another, are C3-C18alkyl; or xe2x80x94CH2xe2x80x94CH(xe2x80x94OH)xe2x80x94CH2xe2x80x94Oxe2x80x94T1;
R19 is C1-C10alkyl or a radical of the formula 
R20 is hydrogen; M; C1-C5alkyl; xe2x80x94NHxe2x80x94C1-C5alkyl, preferably xe2x80x94NH-tert.alkyl; or a radical of the formula xe2x80x94(CH2)mxe2x80x94Oxe2x80x94T2;
T1 and T2 independently of one another, are hydrogen; or C1-C5alkyl; and
m is 1 to 4.
Uppermost of interest are compounds of the formulae (2e) and (2f), in which
R17 and R18, independently of one another, are C3-C18alkyl; or xe2x80x94CH2xe2x80x94CH(xe2x80x94OH)xe2x80x94CH2xe2x80x94Oxe2x80x94T1;
R19 is C1-C10alkyl;
and compounds of the formulae (2g) and (2h), in which
R17 and R18, independently of one another, are C3-C18alkyl or xe2x80x94CH2xe2x80x94CH(xe2x80x94OH)xe2x80x94CH2xe2x80x94Oxe2x80x94T1; and
T1 is hydrogen; or C1-C5alkyl.
Very particularly preferred in this case are triazine compounds of the formula (2e)-(2h), in which R17 and R18 have the same meaning.
Furthermore, interesting triazines correspond to the formula 
in which
R21 is C1-C30alkyl; C2-C30alkenyl; unsubstituted or C1-C5alkyl-mono- or polysubstituted C5-C12cycloalkyl, C1-C5alkoxy-C1-C12alkyl; amino-C1-C12alkyl; C1-C5monoalkylamino-C1-C12alkyl; C1-C5dialkylamino-C1-C12alkyl; a radical of the formula 
R22, R23 and R24, independently of one another, are hydrogen, hydroxyl, C1-C30alkyl, C2-C30alkenyl,
R25 is hydrogen; or C1-C5alkyl;
m1 is 0 or 1; and
n1 is 1 to 5.
Preferred compounds correspond to the formula 
wherein 
Further preferred compounds of formula (1) are those having one of the formulae 
as well as 2,4,6-tris(diisobutyl-4xe2x80x2-aminobenzalmalonate)-s-triazine and 2,4-bis(diisobutyl-4-aminobenzalmalonate)-6-(4xe2x80x2-aminobenzylidenecamphor)-s-triazine.
Particularly preferred compounds of formula (1) are those having the formula: 
in which the individual radicals R26 are the same or different and each is hydrogen; an alkali metal; an ammonium group N(R27)4 in which R27 is hydrogen or an organic radical; C1-C3alkyl; or a polyoxyethylene radical which contains from 1 to 10 ethylene oxide units and the terminal OH group of which may be etherified by a C1-C3alcohol.
In relation to the compounds of formula (25), when R26 is an alkali metal it is preferably potassium or, especially sodium; when R26 is a group N(R27)4 in which R27 has its previous significance, it is preferably a mono-, di- or tri-C1-C4alkylammonium salt, a mono-, di- or tri-C2-C4alkanolammonium salt or a C1-C3alkyl ester thereof; when R27 is a C1-C3alkyl group, it is preferably a C1-C2alkyl group, more preferably a methyl group; and when R27 is polyoxyethylene group, this preferably contains from 2-6 ethylene oxide units.
One preferred class of triazole micronised organic UV absorbers is that having the formula 
in which T1 is C1-C3alkyl or, preferably, hydrogen; and T2 is C1-C4alkyl, preferably t-butyl, or C1-C4alkyl substituted by phenyl, preferably xcex1,xcex1-dimethylbenzyl.
A further preferred class of triazole micronised organic UV absorbers is that having the formula 
in which T2 has its previous significance.
A still further preferred class of triazole micronised organic UV absorbers is that having the formula 
in which
T2 is hydrogen, C1-C12alkyl, preferably t-butyl, or C1-C4alkyl substituted by phenyl, preferably xcex1,xcex1-dimethylbenzyl.
A preferred class of vinyl group-containing amide micronised organic UV absorbers is that having the formula:
R28xe2x80x94(Y)mxe2x80x94COxe2x80x94C(R29)xe2x95x90C(R30)xe2x80x94N(R31)(R32),xe2x80x83xe2x80x83(29)
in which
R28 is C1-C3alkyl, preferably C1-C2alkyl, or phenyl optionally substituted by one, two or three substituents selected from OH, C1-C3alkyl, C1-C3alkoxy or COxe2x80x94OR33,
R33 C1-C3alkyl;
R29, R30, R31, and R32 are the same or different and each is C1-C3alkyl, preferably C1-C2alkyl, or hydrogen;
Y is xe2x80x94NHxe2x80x94 or xe2x80x94Oxe2x80x94; and
m is 0 or 1.
Preferred compounds of formula (29) are 4-methyl-3-penten-2-one, ethyl-3-methylamino-2-butenoate, 3-methylamino-1-phenyl-2-buten-1-one and 3-methylamino-1-phenyl-2-buten-1-one.
A preferred class of cinnamic acid amide micronised organic UV absorbers is that having the formula: 
R33 is hydroxy or C1-C4alkoxy, preferably methoxy or ethoxy;
R34 is hydrogen or C1-C4alkyl, preferably methyl or ethyl; and
R35 is xe2x80x94(CONH)m-phenyl in which m is 0 or 1 and the phenyl group is optionally substituted by one, two or three substituents selected from OH, C1-C3alkyl, C1-C3alkoxy or COxe2x80x94OR4 in which R4 is C1-C4alkyl.
Preferably R35 is phenyl, 4-methoxyphenyl or the phenylaminocarbonyl group.
A preferred class of sulfonated benzimidazole micronised organic UV absorbers is that having the formula 
M is hydrogen or an alkali metal, preferably sodium, an alkaline earth metal, such as magnesium or calcium, or zinc.
Further preferred classes of micronised or micronisable UV absorbers used for the present invention:
p-aminobenzoic acid derivatives, typically 2-ethylhexyl-4-dimethylaminobenzoate
salicylic acid derivatives, typically 2-ethylhexyl salicylate; homosalates; and isopropyl sylicylates;
benzophenone derivatives, typically 2-hydroxy-4-methoxybenzophenone;
dibenzoylmethane derivatives, typically 1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)propane-1,3-dione;
diphenylacrylates, typically 2-ethylhexyl-2-cyano-3,3-diphenylacrylate and 3-(benzofuranyl)-2cyanoacrylate;
3-imidazol-4-yl-acrylic acid and 3-imidazol-4-yl-acrylate;
benzofuran derivatives, preferably 2-(p-aminophenyl)benzofuran derivatives, disclosed in EP-A-582 189, U.S. Pat. Nos. 5,338,539, 5,518,713 and EP-A613 893;
polymeric UV absorbers, such as the benzylidenemalonate derivatives described, inter alia, in EPA-709 080;
cinnamic acid derivatives, typically the 2-ethylhexyl-4methoxycinnamate or isoamylate or cinnamic acid derivatives disclosed, inter alia, in U.S. Pat. No. 5,601,811 and WO 97/00851;
camphor derivatives, typically 3-(4xe2x80x2-methyl)benzylidenebornan-2-one, 3-benzylidene-bornan-2-one, N-[2(and 4)-2-oxyborn-3-ylidenemethyl)benzyl]acrylamide polymer, 3-(4xe2x80x2-trimethylammonium)benzylideneboman-2-one methylsulfate, 3,3xe2x80x2-(1,4-phenylenedime-thine)-bis(7,7-dimethyl-2-oxobicyclo-[2.2.1]heptane-1-methanesulfonic acid) and the salts thereof, 3-(4xe2x80x2-sulfo)benzylidenebornan-2-one and the salts thereof;
2-phenylbenzimidazole-5-sulfonic acids and the salts thereof; and
menthyl-o-aminobenzoate.
In the compounds of formula (1) to (30), C1-C12 alkyl groups may be methyl, ethyl, n-propyl or isopropyl, butyl, pentyl, hexyl, heptyl, octyl, isooctyl, nonyl, decyl undecyl, dodecyl, methyl being preferred; and C1-C3alkoxy groups include methoxy, ethoxy, propoxy and isopropoxy, methoxy and ethoxy being preferred.
C2-C4carboxyalkyl includes carboxymethyl, carboxyethyl, carboxypropyl and carboxyisopropyl, carboxymethyl being preferred.
C5-C8cycloalkyl includes cyclopentyl, cyclohexyl and cyclooctyl.
The compounds of formula (1) to (30) are known.
Preferably, the micronised organic UV absorber, component (a) of the new sun screen agent, has a mean particle size in the range of from 0.01 to 2, more preferably from 0.02 to 1.5, especially from 0.05 to 1.0xcexc.
The sun screen formulation may also comprise as optional component an oil-soluble organic UV absorber which is not micronized. This may be any known oil-soluble organic UV absorber, especially those which are already approved and marketed for cosmetic use. Such oil-soluble organic UV absorbers are described, for instance, in xe2x80x9cSunscreensxe2x80x9d, Development, Evaluation and Regulatory Aspects, Eds.: N. J. Lowe and N. A. Shaath, M. Dekker Inc., New York and Basel, 1990; and Ken Klein, Encyclopedia of UV absorbers for sunscreen products, Cosmetics and Toiletries 107 45-64 (1992).
The oil-soluble, non-micronised UV absorber may be, for example, a p-aminobenzoic acid derivative such as an ester, salt or an amine-modified derivative of p-aminobenzoic acid; a salicylic acid derivative such as an ester or salt thereof; a benzophenone derivative; a dibenzoylmethane derivative; a diphenylacrylate derivative; a benzofuran derivative; a polymeric UV absorber containing one or more silico-organic residues; a cinnamate ester; a camphor derivative; phenylbenzimidazole sulfonic acid and its salts; urocanic acid (3-imidazol-4-yl-acrylic acid) or its ethyl ester; or amenthyl anthranilate.
Specific examples of a p-aminobenzoic acid derivative include 4-aminobenzoic acid (PABA), ethyl dihydroxypropyl PABA having the formula 
PEG-25 PABA having the formula 
in which m, n and x are the same and each is approximately 25, octyl dimethyl PABA having the formula 
and glyceryl aminobenzoate having the formula 
Specific examples of a salicylic acid derivative include homosalate (homomenthyl salicylate) having the formula 
triethanolamine salicylate having the formula 
amyl p-dimethylamino benzoate having the formula 
octyl salicylate having the formula 
4-isopropylbenzylsalicylate having the formula 
Specific examples of benzophenone derivatives include benzophenone-3-(2-hydroxy-4-methoxybenzophenone), benzophenone-4 (2-hydroxy-4-methoxybenzophenone-5-sulfonic acid) and benzophenone-8-(2,2xe2x80x2-dihydroxy-4-methoxybenzophenone).
A specific example of a dibenzoylmethane derivative is butyl methoxydibenzoylmethane [1-(4-tert.-butyl)-3-(4-methoxyphenyl)propane-1,3-dione].
Specific examples of a diphenylacrylate derivative include octocrylene (2-ethylhexyl-2-cyano-3,3xe2x80x2-diphenyl acrylate) and etocrylene (ethyl-2-cyano-3,3xe2x80x2-diphenyl acrylate).
Specific examples of a benzofuran derivative include the 3-(benzofuranyl)-2-cyanoacrylates described in U.S. Pat. No. 5,338,539 or EP 582189, especially the compounds having the formula 
the 2-(2-benzofuranyl)-5-tert.-butylbenzoxazoles described in U.S. Pat. No. 5,518,713 and the 2-(p-aminophenyl)benzofurans described in U.S. Pat. No. 5,362,481.
Specific examples of a polymeric UV absorber containing one or more silico-organic residues are the benzylidenemalonate silicone derivatives disclosed in EP 709080, in particular the compound having the formula 
in which R15 is H or OMe and r is approximately 7; and the polymers of the benzotriazole silicone type described in WO 94/06404, in particular the compound having the formula 
Specific examples of a cinnamate ester include octyl methoxy cinnamate (4-methoxy-cinnamic acid 2-ethylhexyl ester), diethanolamine methoxy cinnamate (diethanolamine salt of 4-methoxycinnamic acid), isoamyl p-methoxycinnamate (4-methoxycinnamic acid 2-isoamyl ester), 2,5-diisopropyl methyl cinnamate, the cinnamido derivatives disclosed in U.S. Pat. No. 5,601,811 and the derivatives described in WO 97/00851.
Specific examples of camphor derivatives are 4-methyl-benzylidene camphor [3-(4xe2x80x2-methyl)benzylidene-bornan-2-one], 3-benzylidene camphor (3-benzylidene-bornan-2-one), polyacrylamidomethyl benzylidene camphor {N-[2(and 4)-2-oxyborn-3-yliden-methyl)benzyl]acrylamide polymer}, trimonium benzylidene camphor sulfate [3-(4xe2x80x2-trimethylammonium)-benzylidene-bornan-2-one methyl sulfate], terephthalydene dicamphor sulfonic acid {3,3xe2x80x2-(1,4-phenylenedimethine)-bis-(7,7-dimethyl-2-oxo-bicyclo-[2.2.1]heptan-1-methanesulfonic acid) and salts thereof and benzylidene camphor sulfonic acid [3-(4xe2x80x2-sulfo)benzylidene-boman-2-one] and salts thereof.
Specific examples of trianilino-s-triazine derivatives include octyl triazine [2,4,6-trianilino-(p-carbo-2xe2x80x2-ethyl-1xe2x80x2-oxy)-1,3,5-triazine, the trianilino-s-triazine derivatives disclosed in U.S. Pat. No. 5,332,568, the trianilino-s-triazine derivatives described in EP 517104, trianilino-s-triazine derivatives disclosed in EP 570838, the trianilino-s-triazine derivatives described in U.S. Pat. No. 5,252,323, the trianilino-s-triazine derivatives described in WO 93/17002-A1 and the trianilino-s-triazine derivatives disclosed in WO 97/03642-A1.
A specific example of a benzotriazole is 2-(2-hydroxy-5-methyl-phenyl)benzotriazole.
Specific examples of hydroxyphenyltriazine derivatives include, e.g. those described EP-A1-775,698, such as 2,4-bis-([4-(2-ethyl-hexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine.
Specific examples of bis-resorcinol-dialkylaminotriazines are, e.g., those described in EP-A1-780,382.
The sunscreen composition of the invention may be formulated as a water-in oil or an oil-in-water dispersion, an oil or oil-alcohol lotion, a vesicular dispersion of an ionic or nonionic amphiphilic lipid, a gel, a solid stick or an aerosol formulation.
When formulated as a water-in oil or an oil-in-water dispersion, the cosmetically acceptable carrier preferably comprises 5 to 50% of an oil phase, 5 to 20% of an emulsifier and 30 to 90% of water, each by weight based on the total weight of the carrier.
The oil phase may comprise any oil conventionally used in cosmetic formulations, especially an emollient e.g., one or more of a fatty alcohol; hydrocarbon oil; a natural or synthetic triglyceride; a wax including esters of long-chain acids and alcohols as well as compounds having wax-like properties; a silicone oil; a fatty acid ester or a fatty alcohol; and lanoline-containing products.
Examples of fatty alcohols include cetyl alcohol, stearyl alcohol, octyldodecanol, cetearyl alcohol and oleyl alcohol; examples of hydrocarbon oils are, e.g., mineral oil (light or heavy), petrolatum (yellow or white), polyethylene, paraffin, squalane, microcrystalline wax, ceresin, polybutene and hydrogenated polyisobutene; examples of a natural or synthetic triglyceride include castor oil, caprylic/capric triglyceride, Japan wax, hydrogenated vegetable oil, sweet almond oil, wheat germ oil, sesame oil, hydrogenated cottonseed oil, coconut oil, wheat germ glycerides, avocado oil, corn oil, trilaurin, hydrogenated castor oil, shea butter, cocoa butter, soybean oil, mink oil, sunflower oil, safflower oil, macadamia nut oil, olive oil, hydrogenated tallow, apricot kernel oil, hazelnut oil and borage oil; examples of a wax including esters of long-chain acids and alcohols as well as compounds having wax-like properties are, e.g., carnauba wax, beeswax (white or yellow), lanolin, candelellila wax, ozokerite, lanolin oil, paraffin, Japan wax, microcrystalline wax, ceresin, jojoba oil, cetearyl esters wax, synthetic jojoba oil, synthetic beeswax and lanolin wax; a silicone oil is e.g. dimethicone or cyclomethicone; examples of a fatty acid ester or a fatty alcohol include isopropyl myristate, isopropyl palmitate, octyl palmitate, isopropyl lanolate, acetylated lanolin alcohol, the benzoate of C12-C15alcohols, cetearyl octanoate, cetyl palmitate, myristyl myristate, myristyl lactate, cetyl acetate, propylene glycol dicaprylate/caprate, decyl oleate, acetylated lanolin, stearyl heptanoate, diisostearyl malate, octyl hydroxystearate, octyl hydroxystearate and isopropyl isostearate; and examples of lanoline-containing products include lanolin, lanolin oil, isopropyl lanolate, acetylated lanolin alcohol, acetylated lanolin, hydroxylated lanolin, hydrogenated lanolin and lanolin wax.
The emulsifier may comprise any emulsifier conventionally used in cosmetic formulations, e.g., one or more of an ethoxylated ester of a natural oil derivative such as a polyethoxylated ester of hydrogenated castor oil; a silicone oil emulsifier such as a silicone polyol; an optionally ethoxylated fatty acid soap; an ethoxylated fatty alcohol; an optionally ethoxylated sorbitan ester; an ethoxylated fatty acid; or an ethoxylated glyceride.
The sunscreen composition of the invention may also comprise further components which are known to perform a useful function in a sunscreen composition. Examples of such further components include, e.g., emollients, skin moisturisers, skin tanning accelerators, antioxidants, emulsion stabilisers, thickening agents such as xanthan, moisture-retention agents such as glycerine, film formers, preservatives, perfumes and colourants.
The sunscreen composition of the invention provides excellent protection of the human against the damaging effects of sunlight, while permitting safe tanning of the skin. Moreover, the sunscreen composition of the invention has a skin waterproofing effect.
The following Examples further illustrate the present invention. Parts and percentages shown therein are by weight unless otherwise stated.